命令对象和hasmany

Question

commandObject当我提交表单时,我正在尝试使用它来验证我的数据.我可以在中验证hasMany关系吗commandObject？我的cenario是这样的.

牵引简单的classeswhith有很多关系:

class Book{
    String nameBook
}

class Author{
    String nameAuthor
    static hasMany = [books:Book]    
}

很简单commandObject,我想在提交表单时验证hasMany.

@grails.validation.Validateable
class MyValidateCommand{

    String nameAuthor
    static hasMany = [books:Book]


    static constraints = {
        nameAuthor nullable:false
        books nullable:false
    }

}

ps:我知道这个commandObject是错误的,它不编译.但我可以这样做吗？

Answer 1

hasMany在GORM中用于域对象中的关联.在命令对象的情况下,为每个域提供不同的命令对象(例如:AuthorCommand和BookCommand)将是一种清晰的方法,命令对象将如下所示:

import org.apache.commons.collections.list.LazyList
import org.apache.commons.collections.functors.InstantiateFactory

//Dont need this annotation if command object 
//is in the same location as the controller
//By default its validateable
@grails.validation.Validateable
class AuthorCommand{
    String nameAuthor
    //static hasMany = [books:Book]

    //Lazily initialized list for BookCommand
    //which will be efficient based on the form submission.
    List<BookCommand> books = 
            LazyList.decorate(new ArrayList(), 
                              new InstantiateFactory(BookCommand.class))

    static constraints = {
        nameAuthor nullable:false
        books nullable:false

        //Let BookCommand do its validation, 
        //although you can have a custom validator to do some 
        //validation here.
    }
}